CT-E2 Exam Domains 2026: Complete Guide to All 16 Content Areas

How the 16 Domains Fit Into the 80-Question Format

The CT-E2 exam is administered by PSI Services LLC on behalf of the Connecticut Department of Consumer Protection and the Electrical Work Examining Board. It is a computer-based, open-book examination consisting of 80 scored questions to be completed in 210 minutes. PSI may also insert up to 10 additional unscored questions into the same session for future exam development - you won't know which items are scored and which aren't, so every question deserves full attention.

Those 80 scored questions are distributed across 16 content domains defined in PSI's published exam outline (bulletin revised February 4, 2026). Some domains, like Raceways and Boxes, carry more weight than others, like Photovoltaics. Understanding this distribution lets you prioritize study time proportionally instead of spreading effort evenly across topics that don't count equally toward your score.

Domain-by-Domain Breakdown

Below is what each of the 16 domains actually tests. This isn't a generic electrical trade overview - it's the specific content area structure PSI uses to build the CT-E2 item bank.

Domain 5: Raceways and Boxes (The Largest Domain)

Raceways and Boxes is the largest of the 16 domains, weighted at eight questions on the 80-item exam. Because it's the single biggest content area, it deserves proportionally more of your study hours than any other domain.

Domain 16: Photovoltaics

Photovoltaics is weighted at six questions, making it one of the more specialized - but still meaningfully sized - domains on the exam. It's also the domain most tied to a distinct set of allowed reference books.

Notably, PSI allows candidates to bring Photovoltaic Systems, third edition, and Convert Your Home to Solar Energy (2010) into the exam room for this domain. The Solar Photovoltaic Systems Installer Trainee Guide (NCCER, 2012) is useful for study but is explicitly a study-only reference - it is not allowed in the testing room, so don't plan on bringing it to your session.

Matching Your Open-Book References to Each Domain

Because the CT-E2 exam is open-book, knowing which allowed reference covers which domain is itself a test-taking skill. PSI permits the NEC or NEC Handbook (2020 or 2023 edition), Ugly's Electrical References (2020 or 2023), OSHA 29 CFR 1926 with the latest amendments (or PSI's listed selections), NFPA 72 National Fire Alarm Code (2013), the two PV references named above, and the National Electrical Safety Code (2012).

• NEC or NEC Handbook - the backbone reference for Domains 1 through 10, 14, and 15
• NFPA 72 (2013) - directly supports Domain 12, Fire Detection and Alarm Systems
• OSHA 29 CFR 1926 - most relevant to Domain 13, Safety Information
• Photovoltaic Systems, 3rd ed. and Convert Your Home to Solar Energy - support Domain 16, Photovoltaics
• Ugly's Electrical References - quick-lookup tables useful across nearly every domain
• National Electrical Safety Code (2012) - relevant background for Domain 15, High Voltage

A Domain-Based Study Timeline

Rather than studying all 16 domains equally, build a schedule that mirrors the exam's actual weighting - heaviest domains get the most weeks, lightest domains get focused review sessions. For a fuller walkthrough of pacing and technique, see the CT-E2 Study Guide 2026: How to Pass on Your First Attempt.

Domain Weight at a Glance

PSI's published bulletin lists the exact weight of each domain; the two figures confirmed publicly are Raceways and Boxes at eight questions and Photovoltaics at six. For the remaining 14 domains, treat the categories above as relative guidance and confirm current weighting directly against the PSI bulletin before your exam window. For more on how the 70% passing threshold interacts with domain distribution, see CT-E2 Passing Score 2026: Exactly What You Need to Pass.

Who Hires E-2 Journeypersons and Why Domains Matter on the Job

Passing the CT-E2 exam and completing the DCP application process (which includes an eligibility review, approval before scheduling, and separate application and renewal fees) results in the E-2 Unlimited Electrical Journeyperson license. E-2 holders perform electrical work only as employees of properly licensed contractors - this is not a standalone contracting credential, and no separate Business and Law exam is required for E-2.

Because of that employment structure, the domains you master aren't just exam content - they map directly to what a licensed contractor will expect you to handle on day one: sizing services and feeders, running and filling raceways correctly, grounding and bonding systems to code, and increasingly, installing PV systems as solar work expands across Connecticut. If you're weighing whether the credential is worth pursuing given the fee structure and renewal obligations, the breakdown in CT-E2 Certification Cost 2026: Complete Pricing Breakdown and the analysis in Is the CT-E2 Certification Worth It? Complete ROI Analysis 2026 lay out the full picture alongside earnings context in the CT-E2 Salary Guide 2026: Complete Earnings Analysis.

If you're still confirming you meet eligibility before you even start mapping domains to a study plan, review CT-E2 Requirements 2026: Eligibility, Prerequisites & How to Qualify - DCP's equivalency pathway specifies 8,000 on-the-job hours and 720 classroom hours for candidates without an approved apprenticeship, and DCP approval must happen before PSI scheduling opens up.

To sharpen your understanding of exactly how challenging each domain feels in practice, compare notes with How Hard Is the CT-E2 Exam? Complete Difficulty Guide 2026, and once you've built domain familiarity, run full-length timed sessions on our CT-E2 practice test platform to see how your recall holds up under the actual 210-minute constraint. Reviewing missed questions by domain on the practice platform is the fastest way to find out whether your gaps are concentrated in Raceways and Boxes, Photovoltaics, or somewhere else entirely.

Frequently Asked Questions